Waterproof and greaseproof paper



Patented Nov. 17, 1925.

PATENT OFFICE.

LESTER KIR SCHBRAUN, OF CHICAGO, ILLINOIS.

WATERPROOF AND GREASEPROOEPAPER.

No Drawing. Application filed August 16, 1922, Serial No. 582,315. Renewed April 30, 1925.

To all whom it may concern:

Be it known that I, LESTER :KIRSCIIBRAUN, a citizen of the United States. residing in the city of Chicago, county ofCook, and State of Illinois, have invented certain new and useful. Improvements in lVaterproof and Greaseproof Paper, of which the following is a specification.

This invention relates to improvements in waterproof and greaseproof paper. and process of making same, and refers more particularly to paper made frbm a mixture of fibrous stock and a specially prepared bituminous emulsion. In its broader aspects the specially prepared emulsion, instead of being used with fibrous stock. may be itself used as av paste.

The invention may be carried out as follows: To a bituminous emulsion prepared as described in my issued Patent, U.- S. No. 1,417,835, I add a quantity of concentrated sulphite liquor. The sulphite liquor and bituminous emulsion are miscible in all which is used as the emulsifying agent, a

quantity of concentrated sulphite of liquor, which combined with the clay, acts as an emulsifying agent, the process being carried on as described 1n said issued patent. When the sulphite liquor, reused. with the clay as an emulsifying agent, it may be noted that the resulting elnulsion has a vqry brown .color which is characteristic of this particular operation.

The emulsion prepared as above described, may be added to paper stock in the boaters and subsequently treated after thorough mixing with formaldehyde, the result of which is to coagulate the sulphite liq nor, gonverting it into such form that it is not, affected by grease.

The stock so prepared may be further treated with alum and then run over a paper machine in the usual manner. When subjecting this to the drying action of the paper machine, the bituminous material eoalesces and the transformation of the colloidal matter of the sulphite liquor into a greaseproof formis thereby accomplished. The resulting product of this treatment is a paper containing the bituminous material as a waterproofing agent in addition to the grease proofing effects imparted by the sul phite liquor. I

The same emulsion may be applied by coating previously prepared paper and applying together in such a form that the film of the waterproof and greaseproof composition is interposed between the plies.

An invention may be carried out in which the colloidal clay is dispensed with and the sulphite liquor alone used with an emulsifying agent. The method of making this emulsion may be, in all essential particulars, similar to the method employed when using clay alone.

I claim as my invention:

1. A paper consisting of fibrous web, bituminous material and the conversion product of sulphite-liquor and formaldehyde.

2. A paper consisting of a fibrous web, fusible waterproofing material, and a grease proofing conversion product of sulphite liquor.

3. A waterproof fibrous. composition, comprising fibrous stock having incorporated therewith a bituminous material dispersed in an aqueous vehicle with sulphite liquor.

4. Awatrproof and greaseproof fibrous composition, comprising fibrous stock having incorporated therewith a bituminous material dispersed in an aqueous vehicle with sulphite liquor, the, composition having been rendered greaseproof by the addition offermaldehyde to the sulphite liquor.

5. A waterproof and greaseproof fibrous composition, comprising fibrous plies having interposed between certain plies a bituminous material dispersed in an aqueous vehicle and rendered greaseproof by the addition of the conversion product of sulph-ite. liquor.

LESTER KIRS'CHBRAUN. 

